Process for the preparation of azeleic acid from 9-octadecenedioic acid

Abstract

The invention relates to a process for the preparation of azelaic acid or alkyl azelate starting from mono-unsaturated 9-octadecenedioic acid or its corresponding alkylester characterized in that the process comprises at least the following step: •reacting the mono-unsaturated 9-octadecene dioic acid or its corresponding alkylester with hydrogen peroxide in the presence of an organic carboxylic acid other than 9-octadecene dioic acid and a suitable catalyst to effect cleavage of the double bond in the mono-unsaturated 9-octadecene dioic acid or its corresponding alkylester. The invention further relates to the azelaic acid or alkyl azelate obtainable by the process according to the invention and to the use of azelaic acid or alkyl azelate or monomers derived there from for the preparation of a polymer, especially a polyamide.

The invention claimed is: 
     
       1. A process for the preparation of azelaic acid or alkyl azelate starting from mono-unsaturated 9-octadecenedioic acid or its corresponding alkylester, wherein the process comprises reacting 9-octadecenedioic acid or its corresponding alkylester in a reaction medium with aqueous hydrogen peroxide in the presence of 10-300 wt. %, based weight % of the 9-octadecanedioic acid, of an organic carboxylic acid other than 9-octadecene dioic acid and a tungsten-based catalyst to effect cleavage of the double bond in 9-octadecenedioic acid or the corresponding alkylester. 
     
     
       2. The process according to  claim 1 , wherein the alkyl groups in the alkyl azelate are independently chosen to contain 1 to 6 carbon atoms. 
     
     
       3. The process according to  claim 1 , wherein the organic carboxylic acid other than 9-octadecene dioic acid is a mono- or dicarboxylic acid with 1-12 carbon atoms. 
     
     
       4. The process according to  claim 1 , wherein the organic carboxylic acid other than 9-octadecene dioic acid is at least 80% soluble in the reaction medium. 
     
     
       5. The process according to  claim 3 , wherein the organic carboxylic acid other than 9-octadecene dioic acid is acetic acid or azelaic acid. 
     
     
       6. Azelaic acid obtained by the process according to  claim 1 . 
     
     
       7. Alkyl azelate obtained by the process according to  claim 1 . 
     
     
       8. A monomer or polymer derived from the alkyl azelate of  claim 7 . 
     
     
       9. A method for preparing a polyamide comprising reacting the alkyl azelate according to  claim 7 , under polyamide formation conditions.